Also the part number I got is the 7-1653. I'm trying to figure out what the OEM part number is so I can track down what cars share it. Mine is a 6MT. I can't seem to find the part# on any OEM GM sites and i don't even know if they call it the same thing (coupler?).

you may want to re-think the prothane style one, you see the shaft has the soft center hanger and moves up and down. the solidness of that style Giubo will not allow the few degrees deflection and will cause a real launch shudder. its my opinion that the issue with the shaft it more the bolts and the spline area. this is where you will see most damage. if you take the torsional deflection out of that stock shaft this may make the known issues more apparent.

you may want to re-think the prothane style one, you see the shaft has the soft center hanger and moves up and down. the solidness of that style Giubo will not allow the few degrees deflection and will cause a real launch shudder. its my opinion that the issue with the shaft it more the bolts and the spline area. this is where you will see most damage. if you take the torsional deflection out of that stock shaft this may make the known issues more apparent.

That actually makes sense. Thanks... I'm already working on returning the two prothane ones.

I didn't actually have a problem before but since I'm upgrading everything else I wonder if I'll have a weak spot. I'm N/A right now but have every bolt one known to man and will be going with a S/C in the future.

Anyway, do you think I'll be safe using the OEM stuff or should I upgrade? If the later, what are my choices?

The hex head bolts that connect the guibo to the defferential are torque to yield bolts and should be replaced. When I went to a local fastener shop to try and find some upgraded bolts they reccomended going with a softer bolt that would have a little more stretch.

The person working there stated that the factory 10.9 bolts are so hard that they will snap. He mentioned having a similar problem with a mercedes. I figured I'd give the grade 8 bolts they mentioned a shot. Haven't been to the track yet though.

I'm hoping if there are any issues ( I haven't had any yet but was swapping gears) a bent bolt will be better then a snapped one.

The hex head bolts that connect the guibo to the defferential are torque to yield bolts and should be replaced. When I went to a local fastener shop to try and find some upgraded bolts they reccomended going with a softer bolt that would have a little more stretch.

The person working there stated that the factory 10.9 bolts are so hard that they will snap. He mentioned having a similar problem with a mercedes. I figured I'd give the grade 8 bolts they mentioned a shot. Haven't been to the track yet though.

I'm hoping if there are any issues ( I haven't had any yet but was swapping gears) a bent bolt will be better then a snapped one.

I thought about replacing bolts anyway since they are "one use only." Where can I get these bolts?